New approach in the determination of interlaminar shear stresses from the results of MSC/NASTRAN

A finite difference technique is applied to the strains and curvatures obtained from MSC/NASTRAN thin plate solutions to determine their derivatives. These quantities are then incorporated into classical thin plate theory to calculate interlaminar shear stresses. Several analyses are performed comparing the interlaminar shear stresses calculated by this method with those calculated theoretically and using MSC/NASTRAN beam theory approach. In all cases, the interlaminar shear stresses calculated by this method compare favorably with theoretical values. In addition, the interlaminar shear stresses are determined using MSC/NASTRAN beam theory approach and the method presented in this paper for a simply supported plate with a 30/-30/-30/30 layup subject to a uniform pressure. The technique presented in this paper can also be applied to other finite element programs.